Remove unused CentOS file for x86_64.

[Alexhuszagh]

No description provided.

[Alexhuszagh]

This file currently isn't used, but it probably should be when we have much more native support for ARM64 hosts. I really don't want to implement this currently, but making it clear this file isn't used it a good idea.

Also, how our process for detecting native Dockerfiles works is that we first locate the non-native Dockerfile, and error if it isn't found. This would cause an issue if we remove this entirely.

bors try --target x86_64-unknown-linux-gnu.centos

[bors]

try

Build succeeded:

• conclusion

[Emilgardis]

I say no to this, I don't see the need since

❯ cargo build-docker-image --platform aarch64-unknown-linux-gnu x86_64-unknown-linux-gnu 
    Finished dev [unoptimized + debuginfo] target(s) in 0.05s
     Running `target/debug/xtask build-docker-image --platform aarch64-unknown-linux-gnu x86_64-unknown-linux-gnu`
[cross] note: Build x86_64-unknown-linux-gnu for aarch64-unknown-linux-gnu
[+] Building 357.2s (23/23) FINISHED                                                                                                                                                                                  
 => [internal] load build definition from Dockerfile.x86_64-unknown-linux-gnu                                                                                                                                    0.0s
 => => transferring dockerfile: 1.17kB                                                                                                                                                                           0.0s
 => [internal] load .dockerignore                                                                                                                                                                                0.0s
 => => transferring context: 223B                                                                                                                                                                                0.0s
 => [internal] load metadata for docker.io/library/ubuntu:20.04                                                                                                                                                  2.4s
 => importing cache manifest from ghcr.io/cross-rs/x86_64-unknown-linux-gnu:main                                                                                                                                 0.0s
 => [internal] load build context                                                                                                                                                                                0.0s
 => => transferring context: 32.38kB                                                                                                                                                                             0.0s
 => [ 1/17] FROM docker.io/library/ubuntu:20.04@sha256:450e066588f42ebe1551f3b1a535034b6aa46cd936fe7f2c6b0d72997ec61dbd                                                                                          2.2s
 => => resolve docker.io/library/ubuntu:20.04@sha256:450e066588f42ebe1551f3b1a535034b6aa46cd936fe7f2c6b0d72997ec61dbd                                                                                            0.0s
 => => sha256:450e066588f42ebe1551f3b1a535034b6aa46cd936fe7f2c6b0d72997ec61dbd 1.42kB / 1.42kB                                                                                                                   0.0s
 => => sha256:72dd010fadf5d9da8197f433fa6ac50179307ce0fc5ac690651518ffa7473885 529B / 529B                                                                                                                       0.0s
 => => sha256:89867091bfb2626393d967e92b55842b547f249ec12469488e0eb5ac1f3c1ae4 1.48kB / 1.48kB                                                                                                                   0.0s
 => => sha256:4e7e0215f4adc2c48ad9cb3b3781e21d474b477587f85682c2e2975ae91dce9d 27.20MB / 27.20MB                                                                                                                 1.3s
 => => extracting sha256:4e7e0215f4adc2c48ad9cb3b3781e21d474b477587f85682c2e2975ae91dce9d                                                                                                                        0.7s
 => [ 2/17] COPY common.sh lib.sh /                                                                                                                                                                              0.1s
 => [ 3/17] RUN /common.sh                                                                                                                                                                                      46.9s
 => [ 4/17] COPY cmake.sh /                                                                                                                                                                                      0.1s 
 => [ 5/17] RUN /cmake.sh                                                                                                                                                                                        7.7s 
 => [ 6/17] COPY xargo.sh /                                                                                                                                                                                      0.0s
 => [ 7/17] RUN /xargo.sh                                                                                                                                                                                       77.2s
 => [ 8/17] RUN apt-get update && apt-get install --assume-yes --no-install-recommends     g++-x86-64-linux-gnu     libc6-dev-amd64-cross                                                                        8.5s
 => [ 9/17] COPY deny-debian-packages.sh /                                                                                                                                                                       0.0s
 => [10/17] RUN TARGET_ARCH=amd64 /deny-debian-packages.sh     binutils     binutils-x86-64-linux-gnu                                                                                                            0.2s
 => [11/17] COPY qemu.sh /                                                                                                                                                                                       0.0s
 => [12/17] RUN /qemu.sh x86_64 softmmu                                                                                                                                                                        157.1s
 => [13/17] COPY dropbear.sh /                                                                                                                                                                                   0.0s
 => [14/17] RUN /dropbear.sh                                                                                                                                                                                    19.5s
 => [15/17] COPY linux-image.sh /                                                                                                                                                                                0.0s
 => [16/17] RUN /linux-image.sh x86_64                                                                                                                                                                          33.0s
 => [17/17] COPY linux-runner base-runner.sh /                                                                                                                                                                   0.0s
 => exporting to image                                                                                                                                                                                           2.0s
 => => exporting layers                                                                                                                                                                                          2.0s
 => => writing image sha256:6a1674b0128506550742de900001125113aa69ad5ec07fe6d78e2453061a7c59                                                                                                                     0.0s
 => => naming to ghcr.io/cross-rs/x86_64-unknown-linux-gnu:local             

works fine

[Alexhuszagh]

I failed to communicate the intent and rationale of this:

1. We need this file to exist and to have the FROM ubuntu:20.04 lines for our build system, since that's how we process native versus non-native Dockerfiles. Otherwise, building a docker image will fail due to being unable to find this Dockerfile.
2. This file can never be used, since it can only be built on an x86_64 host due to assumptions about the compiler/etc., but we already use the Dockerfile.native.centos for that.
3. To implement it for a non-x86_64 host, we'd need something a script to install the entire toolchain like aarch64-linux-gnu-glibc.sh, which I personally am not planning to implement/do anytime soon.
4. It effectively duplicates Dockerfile.native.centos, with just a few hard-coded assumptions, and eventually will become irrelevant.

Marking it as unused, without actually having it do anything, is probably the best solution: I'd rather not add additional logic to our build system just for this file. Dockerfile.x86_64-unknown-linux-gnu is meant for a non-x86_64 host, and that's why it works. Whether or not we need support for an older glibc for this target is irrelevant here right now (it's at best fairly low priority for me): the contents of this file simply are not used.

[Emilgardis]

ofc, I built the wrong image...

anyway, I'd prefer it if we keep the file. Instead I think we can move it to docker/unused/ in one commit, and create a new file in another (to keep line history)

Does that seem fair?

[Alexhuszagh]

We can, I just think the file is practically identical to Dockerfile.native.centos, which just changes x86_64 hard-coded to be abstract for any architecture. The differences are:

4,7d3
< ARG TARGETARCH
< ARG TARGETVARIANT
< ARG CROSS_TARGET_TRIPLE
< 
9,10c5,6
< COPY linux-image.sh native-linux-image.sh /
< RUN /native-linux-image.sh
---
> COPY linux-image.sh /
> RUN /linux-image.sh x86_64
23,29c19,20
< # these need to be present in **both** FROM sections
< ARG TARGETARCH
< ARG TARGETVARIANT
< ARG CROSS_TARGET_TRIPLE
< 
< COPY qemu.sh native-qemu.sh /
< RUN /native-qemu.sh
---
> COPY qemu.sh /
> RUN /qemu.sh x86_64 softmmu
36c27
< COPY linux-runner native-linux-runner base-runner.sh /
---
> COPY linux-runner base-runner.sh /
38,39d28
< ENV CROSS_TARGETARCH=$TARGETARCH
< ENV CROSS_TARGETVARIANT=$TARGETVARIANT
42c31
< ENV CARGO_TARGET_${CROSS_TARGET_TRIPLE}_RUNNER="/native-linux-runner"
---
> ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER="/linux-runner x86_64

Or, linux-image.sh becomes native-linux-image.sh, qemu.sh becomes native-qemu.sh, and linux-runner becomes native-linux-runner. Since the file isn't deleted, its history will stay as well. But I'm fine either way.

[Emilgardis]

after some contemplation, I think this is fine now :)

the image works with cargo build-docker-image --platform aarch64-unknown-linux-gnu x86_64-unknown-linux-gnu.centos but is pretty much unusable

[Alexhuszagh]

bors r=Emilgardis

[bors]

Build failed:

• conclusion

[Alexhuszagh]

Looks like GNU Savannah's temporarily down: will retry later once it's back up.

[Alexhuszagh]

bors retry

[bors]

Build succeeded:

• conclusion